Tonight millions of americans are planning to travel by plane for the holidays as today's safety experts issueed a wakeup call for pilots. They have studied a new tape of that crash in san francisco and are warning it's time to concentrate on people training to fly the planes and not just the technology. Abc's senior national correspondent jim avila takes us through this new tape. Reporter: A new look, from the airport camera, at this devastating accident. Clear skies in july, daylight at san francisco international, this boeing 777 cartwheels down the runway, killing three and threatening the lives of 300 more on board korea-owned asiana air. A fatal crash experts say could have been easily prevented and the national transportation safety board today said could have easily been prevented, questioning why the three pilots depended on computer controls during an emergency and none knew enough about hands-on manual flight to simply throttle up before it was too late. We have an issue that needs to be dealt with with respect to performance. Reporter: The approach has special challenges, it's over water and a steep rate of decent. The pilot at the controls this day in training on the 777 told investigators it was very stressful, very difficult to perform a visual approach with a heavy airplane and he was very concerned. Cockpit communications show it was flying normally. The pilot unfamiliar with local geography asking, is that the golden gate. He had turned off the computerized controls and suddenly an audible warning. The plane is flying too slowly and the captain orders the junior pilot to go around, attempting to abort the landing but it's too late. It's a huge watershed and a big wakeup call. Reporter: One simple move by any of the pilots pushing the throttle forward would have lifted the 777 enough to make the runway and prevent the fatal crash. Instead, these pilots appeared too dependent on computer controls who apparently forgot how to fly out of an emergency by hand. The ntsb calls that automation addiction and it's worried that lack of training is creating a generation of pilots who can no longer fly by hand.

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